Synthesis of Two- and Three-Dimensional Carbon-Based Materials and Their Applications

Department of Energy EngineeringDue to abundant carbon reserves (15th most element in the earth???s crust) and light weight advantage, carbon based materials have been studied to replace rare and expansive inorganic materials in energy materials. Since the discovery of graphene, two dimensional structure, in 2004, two dimensional carbon materials have attracted the attention of researchers from around the globe. Keeping in view the importance of carbon materials, we first produced edge-selective functionalized graphene (EFG) for the production of large-area uniform graphene film for transparent and flexible electrode and transistor by top-down method from graphite to graphene. The resultant graphene films show ambipolar transport properties with sheet resistances of 0.52-3.11 k??/sq at 63-90% optical transmittance. EFG allows solution processing methods for the scalable production of electrically conductive, optically transparent, and mechanically robust flexible graphene films for use in practice. Secondary, we designed and synthesized two dimensional benzimidazole based network polymer for counter electrode in dye-sensitized solar cell (DSSC) to replace platinum. We confirm the effect of thermal annealing and additives of iron from T-HPBI for electrocatalytic activity from the symmetrical dummy cell with two identical electrodes. Furthermore, we also designed and synthesized three-dimensional polymer through solid-state reaction without catalyst at low-temperature for solid sorbent for CO2 capture. The reaction is triggered by metastable crystal lattice energy below its crystal melting temperature. The driving force for the reaction is systematically studied with single-crystal X-ray diffraction and differential scanning calorimetry.ope

Testing for Non-Nested Conditional Moment Restrictions Using Unconditional Empirical Likelihood

We propose non-nested hypotheses tests for conditional moment restriction models based on the method of generalized empirical likelihood (GEL). By utilizing the implied GEL probabilities from a sequence of unconditional moment restrictions that contains equivalent information of the conditional moment restrictions, we construct Kolmogorov-Smirnov and Cramer-von Mises type moment encompassing tests. Advantages of our tests over Otsu and Whang's (2007) tests are: (i) they are free from smoothing parameters, (ii) they can be applied to weakly dependent data, and (iii) they allow non-smooth moment functions. We derive the null distributions, validity of a bootstrap procedure, and local and global power properties of our tests. The simulation results show that our tests have reasonable size and power performance in finite samples.Empirical likelihood, Non-nested tests, Conditional moment restrictions

KSU Chorale Ensembles

Leslie J Blackwellhttps://digitalcommons.kennesaw.edu/musicprograms/1661/thumbnail.jp

An Evening With Schubert

Kennesaw State University School of Music presents A Night with Schubert, directed by Dr. Leslie J. Blackwell.https://digitalcommons.kennesaw.edu/musicprograms/1725/thumbnail.jp

Mechanism of DNA target site recognition by group II introns TeI3c and GsI-IIC and splicing activity of GsI-IIC reverse transcriptase

Mobile group II introns are self-catalytic ribozymes found in bacteria and eukaryotic organelles. They can mobilize within the genomes by retrohoming, which involves RNA-catalyzed splicing followed by the excised intron reverse splicing into a target site. Both RNA splicing and retrohoming are facilitated by an intron-encoded reverse transcriptase (RT). Mobile group II introns are of interest as evolutionary ancestors of spliceosomal introns in higher organisms, for their use as bacterial gene targeting vectors known as targetrons, and as a source of thermostable group II intron reverse transcriptases (TGIRTs) for RNA-seq. The focus of this master’s thesis is on two thermophilic group II introns found in bacterial thermophiles: the subgroup IIB intron TeI3c and the subgroup IIC intron GsI-IIC. The TeI3c intron is known to rely on base pairing interaction between exon-binding site sequences 1/2 (EBS1/2), within the intron RNA, and intron-binding site sequences 1/2 (IBS1/2) in the 5’ exon of its target DNA, but it is not clear what targeting rules dictate one target sequence to be better or worse than others. I studied the targeting rules of TeI3c during retrohoming by using randomized libraries and next-generation sequencing followed by computational analysis of the sequence data. Understanding the targeting rules of TeI3c can be the important step in the development of thermostable targetron, which can be useful for metabolic engineering in the biofuel industry. Unlike TeI3c, which relies primarily on base pairing for DNA target recognition, the GsI-IIC intron recognizes a 5’-exon hairpin secondary structure of the target DNA. However, the secondary structure requirements of good targets have not been studied. I studied the secondary structure requirements during GsI-IIC retrohoming by using doped target libraries and next-generation sequencing to find conserved positions within a hairpin target site followed by mobility assays on different target sites with mutated conserved positions. Finally, I studied the forward splicing of GsI-IIC intron by comparing different hairpin target sites including the same mutated target sites tested for their mobility efficiency. These experiments address whether the 5’-exon hairpin structure is recognized similarly for RNA splicing and intron mobility.Cellular and Molecular Biolog

Relaxation of superfluid turbulence in highly oblate Bose-Einstein condensates

We investigate thermal relaxation of superfluid turbulence in a highly oblate Bose-Einstein condensate. We generate turbulent flow in the condensate by sweeping the center region of the condensate with a repulsive optical potential. The turbulent condensate shows a spatially disordered distribution of quantized vortices and the vortex number of the condensate exhibits nonexponential decay behavior which we attribute to the vortex pair annihilation. The vortex-antivortex collisions in the condensate are identified with crescent-shaped, coalesced vortex cores. We observe that the nonexponential decay of the vortex number is quantitatively well described by a rate equation consisting of one-body and two-body decay terms. In our measurement, we find that the local two-body decay rate is closely proportional to $T^2/\mu$, where $T$ is the temperature and $\mu$ is the chemical potential.Comment: 7 pages, 9 figure